This invention relates to novel processes for making compounds useful as complexing agents for various metal and/or alkaline earth metal ions.
It is well recognized that compounds having the ability to complex metal and/or alkaline earth metal ions which contribute to water "hardness", e.g. magnesium and calcium are useful in a variety of applications such as water treatment (e.g., softening, scale inhibition). (It is noted that some complexing agents also exhibit the ability of preventing precipitation of hardness ions from water even when used in quantities stoichiometrically insufficient to sequester the hardness ions. Such agents are said to exhibit "threshold" effect.) Additionally, some such compounds exhibit the ability to enhance, potentiate or supplement the cleaning ability of detergent formulations and are useful as functional ingredients thereof. Conventionally, such ingredients are referred to as detergency "builders" although in some applications, e.g. machine dishwashing formulations, the functionality of such compounds appears to be more than or different from a mere "building" of the performance of other ingredients of the formulation.
The provision of novel complexing agents and methods for their synthesis has long been a continuing objective of those skilled in the art in view of the varied, recognized utilities of such materials.